rest mock service: clicking on the wsdl crashes webui

I have a project with mostly XML/SOAP mock services, and one JSON/REST mock service.

I deployed a WAR file with all services. In the WebUI-interface, I can navigate to the WSDL's of the SOAP services.

However, when I click on that same link for the REST-service, WebUI crashes. Refreshing the page doesn't help.

It seems like the mock-service itself keeps working (at least for the soap services).

I tried creating the WAR file with SoapUI 5.2.1 and 5.3.0, on two different servers. All had the same problem.

What can I do to avoid this problem? It's quite natural for the JSON/REST service to not have a WSDL, but I don't expect a crash.